Radio remote control receiver



Aug. 22, 1944. R. s. TICE RADIO REMOTE CONTROL RECEIVER Filed Nov. 13,1942 INVENTOR, REUBEN s. 7761:.

A T TORNEYS.

Patented Aug. 22 1944 UNITED STATES NT FF 1 CE 2,356,364

RADIO REMOTE CONTROL RECEIVER ReubenS. Tice, Monterey, Calif.

Application'Novembe'r 13, 1942, Serial No. 465,465

'6 Claims.

.My invention relates to radio remote control receivers, and isparticularly applicable for use as an alert receiver operating inaccordance with the operating conditions of a radio transmitter, eithercontinuous wave or voice modulated.

Among the objects of my invention are: To provide a radio receiver thatis'capable of automatically operating a relay when a radio transmittingstation eithergoes off :the air, or transmits a warning signal includinginterruption of transmission; to provide such a system which does notrely uponany modulated output of the radio transmitter; to providearelay operating radio receiver that is automatically resetting, andwhich can operate untended in accordance with the interruptions of aradio signal; to provide an alert receiver capable of operating an.alarm or controlling lights upon interruption or cessation of a signalfrom the radio station to applicable to other apparatus, and that Ido-not .limit myself in any way to the apparatus of the presentapplication, as I may adopt various other apparatus embodimentsutilizing the method, within the scope of the appended claims. There aremany radio receivers available today, which are primarily designed asremotely controlled receivers operating as alert alarms, for example, inaccordance with a signal from local broadcast, police or specialemergency stations. Such receivers, however, practicallyinvariablyoperate by virtue of the modulated component of the localradio station output. When continuous wave operation is utilized, rathercomplicated circuits are required, and usually special transmittingstations. 4

My present invention, however,

greatly increases the reliability of operation of remotely mains, sothat all the radio-frequency energy received is modulated at thereceiver at control signal frequency. This locally modulated radio-'frequency may then be further amplified, detected and amplified asaudio power, and the output passed to a trigger tube such as aThyratron, whose anode is also supplied by the local controlsignal'frequency.

The output of the trigger tube ma then be used to actuate a relay, "andpreferably a relay having .a certain amount of time delay. 'The outputrelay may be operated either directly from the trigger tube or throughthe medium of more sensitive relay acting directly from the output ofthe trigger tube. In this mannenth'e entire amplitude of received andamplified energy is available for actuating the trigger tube.

' 'When transmission from the transmitter to which the receiver is tunedceases, the receiver immediately ceases operation, because the controlsignal frequency cannot be amplifiedin the radio-frequency stagesfollowing the modulator stage. The trigger tube, therefore, alsoimmediately ceases operationupon cessation of transmission from theradio transmitter operating the relay. However, upon resumption of thetransmitter the entire set becomes active again, the trigger tube isoperated, and the work circuit conditions are immediately reversed Theentire operation is automatic, the receiver can be placed in distantlocations without supervision, and if desired, the receiver output canbe coded to perform specialdiitie's, although such a coding system is nopart of the present inventron. I

In the drawing, the figure is a circuit diagram showing one manner bywhich a receiver may be modulatedby a local alternating current such as,for example, from the local alternating power mains, to produce reliableand accurate control of an output relay.

Referring, therefore, directly 'to this diagram for a more detaileddescription of iny invention, a radio receiver is provided with thecustomary type of antenna 2 and connected to a radio-frequency inputtransformer 3 tuned, as is cus tomary, fby variable capacity ii, thesecondary 5 of .the transformer energizing grid '6 of a firstradio-frequency amplifier and modulator tube '1, preferably of the typehaving a heater '8, and an indirectly heated cathode 9 grounded throughbiasing circuit Ii].

Theradio-frequency transformer 3' is provided with the usual groundedprimary and secondary terminals H, Screen [2 and anode M of tube 1 arejoined through the primary 15 of a second radio-frequency transformer i6and connected to anode supply and control frequency line 18. Primary istuned by condenser H, and screen i2 and anode [4 are directly connectedthrough primary [5 to the control frequency line 18 to one side of A. C.mains 20, the other side 2| of these mains being grounded through acontrol switch 22. Line [8 is also grounded through radio-frequencyby-pass condenser 22. Secondary 2!! of radio-frequency transformer i6 istuned by variable capacity 25 and one side of secondary 2:1 is led togrid 26 of the second radio-frequency amplifier tube 21, the screen 28and anode 29 of this tube being joined by inductance 30 tuned byvariable capacity 3| and connected to supply line 32.

The inductance 39 of the tuned anode circuit forms the primary of athird radio-frequency transformer 33, the secondary 34 of which isconnected to a combined detector and first audio amplifier tube 36,comprising diode detector elements 3'! and amplifier elements 38 coupledthereto, as is well known in the art.

Output anode 39 of the amplifier section 38 is resistance coupled byresistors 40 and capacity 4i to the grid 42 of audio amplifier tube 43,the screen 44 and anode 45 of which are connected together through theprimary 46 of an audiofrequency transformer 41, the screen and anodepotential being supplied by connections from anode supply line 32through lead 49. Anode 39 of tube 36 amplifier section 38 is similarlysupplied through line 50.

Secondary 5| of audio-frequency transformer 4! is connected throughoutput circuit 52 to a trigger or Thyratron tube 55, one side of circuit52 being connected to cathode 55 of this trigger tube, the other side ofthe circuit being connected to the firing electrode 51 of this tube.Anode 58 of the trigger tube is supplied with alternating current atcontrol signal frequency from mains 29 through a relay winding 60, whichcontrols any type of load circuit desired. Such load circuit may includea time delay relay 6| which may in turn control a coding circuit (notshown), all depending upon the use to which the receiver is to be put.

Anode potential for the receiver proper is obtained, as is customary, bythe use of rectifier 65 supplying current to anode supply line 32through the filter circuit 66.

In operation, the radio-frequency circuits are tuned to the frequency ofa radio transmitter station by their variable capacities which may, ifdesired, be linked. The radio transmitting station may be a continuouswave station, or may be voice modulated such as, for example, abroadcast station. The received radio-frequency is amplified in tube 1,but the alternating current energization of the plate of this tube bythe control signal frequency from mains 20 causes the incomingradio-frequency to be completely interrupted or modulated at controlsignal frequency in the output of this tube. This locally modulatedradio-frequency is then amplified in radio-frequency amplifier 21,detected in portion 3'! of tube 36, amplified as audio-frequency in theaudio-frequency portion 38 of tube 36, and still further amplified inaudio-frequency amplifier tube 43, so that the output of transformer 41is, while the receiver is receiving radio-frequency from thetransmitter, alternating current only at control signal frequency. Thisalternating current is then passed to the trigger tube, the anode ofwhich is also supplied with alternating current from the control signalfrequency mains 20.

The trigger tube will fire or ignite to pass current whenever theaudio-frequency output of transformer 41 is positive coincidentally withthe positive excitation of the trigger tube anode, which will be duringthe time radio-frequency is being received, and amplified in firstradio-frequency amplifier and modulator tube 1. When, however,radio-frequency is no longer being received by antenna 2, due tocessation or interruption of the radio station to which the receiver istuned, the control signal frequency continuing in the primary l5 ofsecond radio-frequency transformer l8 cannot modulate anyradio-frequency, as tube 1 will not be operating. Consequently, noamplification of any kind can take place in tube 21, or in the remainderof the system. The trigger tube, therefore, at once loses its ignitingpotentials and ceases operation. The time delay relay when used, willoperate, providing the interruption is longer than the time delay builtinto the relay.

The principal reason for using a time delay relay in a system of thischaracter, is to eliminate any possibility of operation of such relaycontrolled circuit when short and accidental interruptions take place inthe output of the radio transmitter to which the receiver is tuned.

At any time after the receiver has once ceased operation because of lackof input radio-frequency, this input is again received, the entire setwill again pass the locally modulated current, the trigger tube willagain be energized, and the time delay relay 6| will operate by virtueof the output of the trigger tube and the energization of relay 60.Thus, the time delay relay will automatically operate in bothdirections, according to the radiofrequency reception.

It will be noted that there are many advantages inherent in the circuitjust above described. In the'first place, the receiver will operate tocontrol relay G0 on either a broadcast station when it is being voicemodulated or on the same broadcast station without voice modulation. Ina like manner the receiver will operate from a station which is adaptedto emit continuous waves only under interruption control.

Furthermore, inasmuch as the radio-frequency circuits are made tunable,the receiver is operative throughout its range on any radio station towhich it may be tuned, irrespective of whether the station is voicemodulated or not. No dependence need be placed upon the modulatedcomponent of the received radio-frequency wave and, in fact, all of theenergy of the received wave is available as a signal to be modulated,amplified, rectified, and further amplified as audio-frequency for usein operating the trigger tube.

The receiver is positive in action, is not operable by any usual staticconditions. Even if static should be at times sufiiciently strong toblank out the operation of the first radio-frequency amplifier modulatortube I, the time delay relay can be set to take care of such momentaryinterruptions. Obviously, also, the relay" can be utilized to eitherenergize or de-energize the time delay relay 6|, either in phase withthe energization or de-energization of trigger tube 55 or in oppositephase.

Inasmuch as the receiver becomes completely inoperative or completelyoperative in accordance with the on or off conditions of a distant radiotransmitter, the time delay relay 6| can be utilized to operate a codingdevice in accordance with the type and sequence of coded signalsreceived by antenna 2 providing only, of course, that such codingsignals shall be timed properly so that they will not interfere with thetime delay response of relay 6 I.

It will thus be seen that I have provided a very simple and reliablemanner of rendering a radio receiving circuit completely operative, orcompletely inoperative in accordance with the oper ating conditions of adistant radio set whether this radio transmitter be voice modulated orunmodulated at the transmitter, by using local modulation of thereceived wave at a relatively low control frequency. The receiver iscompletely unresponsive to the control signal alone. Consequently, whileI have shown one particular circuit by which this result can beaccomplished, I do not wish to be limited to the particular means andmethod of modulating tube 1 nor to the particular type of followingcircuits shown, as it will be obvious to those skilled in the art thatother means and methods of modulation are fully equivalent, and thatother types of control signal exclusion circuits may be used to obtainthe same result.

Having described my invention, I claim:

1. A radio receiver controllable in accordance with the transmissionfrom a radio transmitter, a radio-frequency responsive tube, means forenergizing said tube with a radio-frequency signal transmitted by saidtransmitter, a local source of relatively low control frequencyoscillations connected to modulate the output of said radio-frequencyresponsive tube, a radio-frequency amplifier tube responsive to thereceived radio-frequency signal frequency only, means for detecting andamplifying at control signal frequency the output of saidradio-frequency amplifier tube, a trigger tube having an outputelectrode and a firing electrode, means for applying said control signaldirectly to said output electrode, and means for applying said rectifiedand amplified control signal to said firing electrode.

2. A radio receiver controllable in accordance with the transmissionfrom a radio transmitter, a radio-frequency responsive tube, means forenergizing said tube with a radio frequency signal transmitted by saidtransmitter, a local source of relatively low control frequencyoscillations connected to modulate the output of said radiofrequencyresponsive tube, a radio-frequency amplifier tube responsive to thereceived radio-frequency signal frequency only, means for detecting andamplifying at control signal frequency the output of saidradio-frequency amplifier tube, a trigger tube having an outputelectrode and a firing electrode, means for applying said control signaldirectly to said output electrode, means for applying said rectified andamplified control sig nal to said firing electrode, and a work circuitcontrolled by current delivered by said output electrode.

3. A radio receiver controllable in accordance with the transmissionfrom a radio transmitter, a radio-frequency responsive tube, means forenergizing said tube with a radio-frequency signal transmitted by saidtransmitter, a local source of relatively low control frequencyoscillations connected to modulate the output of said radiofrequencyresponsive tube, a radio-frequency amplifier tube responsive to thereceived radio-frequency signal frequency only, means for detecting andamplifying at control signal frequency the output of saidradio-frequency amplifier tube, a trigger tube having an outputelectrode and a firing electrode, means for applying said control signaldirectly to said output electrode, means for applying said rectified andamplified control signal to said firin electrode, a work circuitcontrolled by current delivered by said output electrode, and a relayoperated by current delivered by said output electrode.

4. In a radio receiver having a vacuum tube amplifier stage responsiveto received radio-frequency only, detecting and audio-frequencyamplifying stages, means for receiving a radio-frequency signal from aradio transmitter, means for modulating said received signal afterreception thereof with audio-frequency control signal means forenergizing said vacuum tube amplifier stage with said modulated signal,a trigger tube having an output electrode and a firing electrode, meansfor applying said control signal directly to said output electrode, andmeans for applying said rectified and amplified control signal to saidfiring electrode.

5. In a radio receiver having a vacuum tube amplifier stage responsiveto received radio-irequency only, detecting and audio-frequencyamplifying stages, means for receiving a radio-frequency signal from aradio transmitter, means for modulating said received signal afterreception thereof with audio-frequency control signal means forenergizing said vacuum tube amplifier stage with said modulated signal,a trigger tube having an output electrode and a firing electrode, meansfor applying said control signal directly to said output electrode,means for applying said rectified and amplified control signal to saidfiring electrode, and a work circuit controlled by current delivered bysaid output electrode.

6. In a radio receiver having a vacuum tube amplifier stage responsiveto received radio-frequency only, detecting and audio-frequencyamplifying stages, means for receiving a radio-frequency signal from aradio transmitter, means for modulating said received signal afterreception thereof with audio-frequency control signal means forenergizing said vacuum tube amplifier stage with said modulated signal,a trigger tube having an output electrode and a firing electrode, meansfor applying said control signal directly to said output electrode,means for applying said rectified and amplified control signal to saidfiring electrode,.a work circuit controlled by current delivered by saidoutput electrode, and a relay operated by current delivered by saidoutput electrode.

REUBEN S. 'IICE.

